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RT9501A/B
Advanced Lithium-Ion Linear Battery Charger
General Description
Features
The RT9501 is a single Lithium-Ion or Lithium-Polymer
cell linear battery charger which is designed for compact
and cost-sensitive handheld devices. It combines charge
status indication, charge termination, battery temperature
monitoring, and high accuracy current and voltage
regulation in a MSOP-8 package.
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For Single Lithium-Ion or Lithium-Polymer Cell
Battery Pack (4.1V or 4.2V)
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A Few External Components are Required
Precharge, Constant Current, Constant Voltage
Modes
Battery Temperature Monitor
Charge Status Indication
Automatic Battery Recharge
Charge Termination Detect
Auto Low Power Sleep Mode when VDD Power is
Removed
MSOP-8 Package
RoHS Compliant and 100% Lead (Pb)-Free
The RT9501 charges the battery in three modes,
precharge, constant current, constant voltage. If the
battery voltage is below the precharge threshold VO(MIN),
the RT9501 precharges the battery with a lower
conditioning current. After precharge, the RT9501 applies
a constant current to the battery. An external senseresister sets the charge current. The constant voltage
mode continues until the battery reaches the regulation
voltage.
The battery temperature is continuously measured by an
external thermistor through the TS pin. The RT9501
inhibits charge until the temperature is within the range
defined by users.
Ordering Information
RT9501
Package Type
F : MSOP-8
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Voltage Version
A : 4.1V
B : 4.2V
Note :
Richtek products are :
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RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
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Applications
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Digital Cameras
PDAs
Cellular Phones
Information Appliance
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Pin Configurations
(TOP VIEW)
VDD
TS
STAT
GND
1
8
2
7
3
6
4
5
BATT
CS
FB/CE
CC
MSOP-8
Suitable for use in SnPb or Pb-free soldering processes.
DS9501A/B-09 April 2011
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RT9501A/B
Typical Application Circuit
D1
VIN
Q1
RCS
Battery
Pack
C2
0.1uF
to
1uF
R4
1k
+
NTC
5
CC
FB/CE 6
7 CS
1
BATT 8
4
RT1
2
VDD
GND
TS
STAT 3
C1
0.1uF
RT2
R3
2k
GND
Figure 1. Application circuit using P-Channel MOSFET
VIN
RCS
Battery
Pack
Q1
C2
0.1uF
to
1uF
R1
1k
+
NTC
5
7
1
CC
FB/CE
6
CS
BATT
8
TS
STAT
3
VDD
4 GND
C1
0.1uF
GND
RT1
2
R3
2k
RT2
Figure 2. Application circuit using PNP transistor
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DS9501A/B-09 April 2011
RT9501A/B
Functional Pin Description
Pin Name
Pin Function
VDD
Supply Voltage Input.
TS
Temperature Sense Input. Input from battery temperature monitoring circuit.
STAT
Charge Status Output. 3-state status indication of charge, charge complete and temperature fault or
disable or sleep mode.
GND
Ground.
CC
Charge Control Output. Current output to drive on external PNP transistor or P-Channel MOSFET
for current and voltage regulation.
FB/CE
External Feedback Input or Charge Enable Function. Input from controller or finely adjust the battery
regulated voltage with external voltage divider.
CS
Current Sense Input. Charge current is sensed according to the voltage drop from supply voltage to
this pin.
BATT
Battery Voltage input. Input directly from battery voltage.
Function Block Diagram
-
BATT
VDD
Sleep Mode Detection
+
VDD
CC
Control
-
Internal FB
FB/CE
Feedback
Determination
& Enable Control
CV
Control
Precharge
Control
Logic
+
Recharge
CS
VREF1
FB2
VREF2
+
+
TS2 Trip
+
+
TS1 Trip
-
TS
FB2
+
FB2
VREF3
FB2
VREF4
CC
VDD
STAT
GND
FB2
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RT9501A/B
Absolute Maximum Ratings
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(Note 1)
Supply Voltage --------------------------------------------------------------------------------------------------------- −0.3V to 7V
Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C
Power Dissipation, PD @ TA = 25°C
MSOP-8 ----------------------------------------------------------------------------------------------------------------- 300mW
Package Thermal Resistance
MSOP-8, θJA ------------------------------------------------------------------------------------------------------------ 80°C/W
Operation Junction Temperature Range -------------------------------------------------------------------------- −40°C to 125°C
Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
ESD Susceptibility (Note 2)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
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(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 4.5V to 7V
Junction Temperature Range ---------------------------------------------------------------------------------------- −20°C to 70°C
Electrical Characteristics
(TA = 25°C, unless otherwise specification)
Parameter
Symbol
Test Condition
Min
Typ
Max
Units
Operating Current
IDD(OPE)
4.5V < V DD < 7V,
Excluding external loads
--
1
2
mA
V DD Sleep Current
IDD(SLP)
VBATT −VDD ≥ 0.2V
--
--
3
μA
Input Bias Current @ BATT pin IBATT
VBATT = VO(REG),
VBATT − VDD ≥ 0.2V
--
1.5
2.5
μA
Input Bias Current @ CS pin
ICS
VCS = 5V, VBATT − VDD ≥ 0.2V
--
--
1
μA
Input Bias Current @ TS pin
ITS
VTS = 5V, VBATT − VDD ≥ 0.2V
--
--
1
μA
Input Bias Current @ FB/CE pin ICE
VCE = 5V, VBATT − VDD ≥ 0.2V
--
--
1
μA
Input Low Voltage @ CE pin
VCE
--
--
1.5
V
Input High Voltage @ CE pin
VCE
VDD–1.5
--
--
V
Feedback Voltage @ FB pin
VFB
2.048
2.10
2.152
V
Output Voltage
VO(REG)
RT9501A
4.059
4.10
4.141
V
RT9501B
4.158
4.20
4.242
V
Current Regulation Threshold
VI(SNS)
100
110
121
mV
Charge Terminated Current
Detect Threshold
V(TERM)
2
12
22
mV
Lower Temperature Threshold
VTS1
29.1
30
30.9
%VDD
Upper Temperature Threshold
VTS2
58.3
60
61.8
%VDD
Precharge Threshold
VO(MIN)
2.8
2.9
3.0
V
Precharge Current Regulation
V(PRE)
4
14
24
mV
Recharge Threshold
VO(RCH)
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VI(SNS) = V DD – VCS
VO(REG) – V O(REG)– V O(REG) – V
140mV 100mV
60mV
To be continued
DS9501A/B-09 April 2011
RT9501A/B
Parameter
Symbol
Test Condition
Min
Typ
Max
Output (Low) Voltage @ STAT pin VSTAT(LOW) IOL = 10mA
--
0.4
0.6
Output (High) Voltage @ STAT pin VSTAT(HIGH) IOH = 5mA
VDD –0.5
--
--
Units
V
Output Low Voltage @ CC pin
VCC(LOW)
IO(CC) = 5mA ( sink )
--
--
1.5
V
Sink current @ CC pin
ICC(SINK)
Not to exceed power rating
specification (PD)
5
--
40
mA
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2. Devices are ESD sensitive. Handling precaution is recommended.
Note 3. The device is not guaranteed to function outside its operating conditions.
DS9501A/B-09 April 2011
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RT9501A/B
Application Information
Charge Profile
Precharge
mode
Constant current
regulation mode
Constant voltage regulation
and charge termination mode
Recharge
mode
Regulation voltage
Recharge voltage
Regulation current
Precharge threshold
voltage
Precharge current =
Charge termination current
Figure 3. Typical charge profile
Detection
Constant Current Regulation Charge Mode
First, the FB/CE pin must connect to VDD or a voltage
divider to enable the charge function. And then if a battery
is already inserted and the input power source is absent,
the RT9501 will enter sleep mode to prevent draining
power from battery. When input power source and battery
are both existed, another detection is the battery
temperature. The TS pin voltage must be in the allowed
range as shown in Figure 6 and the electrical
characteristics, and then the RT9501 will start the charge
cycle according to the battery voltage conditions.
When the battery voltage is between the precharge
threshold VO(MIN) and the regulation voltage VO(REG), the
RT9501 starts the constant current regulation charge
mode. RT9501 monitors charge current with voltage drop
between two terminals of a sense-resistor, RCS, which
connects to pin VDD and CS. The following equation can
calculate the desired charging current.
IO(REG) =
Precharge Mode
When the battery voltage is lower than the precharge
threshold VO(MIN), the RT9501 begins to charge the battery
in precharge mode. In this condition, the precharge current
is set at approximately 10% of the constant regulation
current. The purposes of small precharge current are to
minimize the power dissipation on the external switch
during the precharge period and to revive deeply
discharged battery cells.
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VIN
VI(SNS)
RCS
RCS
Q1
Battery
R4
CC
FB/CE
CS
BATT
VDD
GND
TS
STAT
Figure 4
DS9501A/B-09 April 2011
RT9501A/B
Constant Voltage Regulation and Charge
Termination Mode
When the battery voltage reaches the regulation voltage
VO(REG), the constant voltage feedback control starts, and
then the charge current begins to decrease as the typical
charge profile shown. As the charge current decreases
to lower than charge terminated current threshold, the
RT9501 will terminate the charge cycle.
VIN
RCS
Battery
Pack
Q1
R4
RT1
+
C2
FB/CE
CS
CC
BATT
VDD
STAT
RT2
TS
GND
Thermistor
Figure 5
Recharge Mode
After the charge termination mode, if the battery voltage
falls to lower than the recharge threshold voltage VO(RCH),
the RT9501 will begin a new charge cycle according to
the battery voltage.
VDD
Temperature Fault Range
VTS2
Normal Temperature Range
VTS1
Battery Temperature Detection
The RT9501 continuously detects the battery temperature
by measuring the TS pin voltage. A NTC or PTC
thermistor can parallel with RT2 to deviate the TS pin
voltage. (As shown in Figure 5) The TS pin voltage must
be within normal temperature voltage range that is shown
in Figure 6 and electrical characteristics, and then RT9501
can start working normally.
The RT1 and RT2 can be derived from following equations.
For NTC Thermistors:
RT1 =
RT2 =
5 × RTH × RTL
3 × (RTL - RTH)
5 × RTH × RTL
Temperature Fault Range
GND
Figure 6
FB/CE Pin Functions
This pin has two functions, one is to enable/disable the
charge function, and the other is to finely adjust battery
regulation voltage. Connect this pin to VDD to enable
RT9501, and connect to ground to disable it (Figure 7). If
this pin is connected to a voltage divider as shown in
Figure 8, it can be a 2.1V reference voltage to adjust the
output regulation voltage as desired.
[(2 × RTL) - (7 × RTH)]
RCS
VIN
For PTC Thermistors:
RT1 =
RT2 =
3(RTH - RTL)
[(2 × RTH) - (7 × RTL)]
Where RTL is the resistance value in lowest desired
operation temperature and RTH is the resistance value in
highest desired operation temperature. The resistances
of thermistors are specified by the thermistor
manufacturer. If the temperature monitoring function is
not desired, there's an easy method to set RT1 and RT2 at
the same value and disconnect the thermistor to disable
this function.
DS9501A/B-09 April 2011
Battery
RCE
5 × RTH × RTL
5 × RTH × RTL
Q1
R4
GPIO
CE
CC
CS
BATT
VDD
STAT
TS
GND
Figure 7. For CE pin Function
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RT9501A/B
VIN
RCS
Q1
Battery
R4
RFB1
FB
CC
CS
BATT
VDD
STAT
RFB2
TS
GND
Figure 8. For FB pin Function
VO(REG) = 2.1× (1+
RFB1
RFB2
Selecting Input/Output Capacitor
In analog circuit applications, to place a high-frequency
decoupling capacitor nearby the controller IC between
input power source and ground is very important. A 0.1uF
ceramic is recommended. If a high ripple and noise input
power is chosen, it should have enough capacitance to
reduce the disturbance.
A 0.1uF to 1uF output capacitor is recommended to control
the output voltage and keep the output voltage ripple small
when the battery is disconnected.
) V
Charge status indication
The RT9501 indicates the status of the charger on the 3state STAT pin. The following table shows the statuses of
this pin.
Condition
STAT Pin
In battery charging cycle
High
Charge cycle completed
Low
Temperature fault or charge
function disable or sleep mode
High Impedance
Selecting an External PNP Pass-Transistor or
P-Channel MOSFET:
The RT9501 drives an external PNP transistor or
P-Channel MOSFET to control the charging current. The
specifications must be concerned are the voltage and
current rating and package power dissipation. The external
switch is performed as a linear regulator. The maximum
power loss occurs when the constant current regulation
starts at the beginning, and it can be calculated
approximately from following equation:
P D(MAX) = I(SNS) × (V DD - 0.1V - 2.8V)
I(SNS) is the constant regulation current.
The minimum voltage drop between the sense-resistor
is 100mV, and the minimum precharge threshold voltage
is 2.8V.
The external pass device with PCB heatsinking must be
rated for the maximum power dissipation.
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DS9501A/B-09 April 2011
RT9501A/B
Outline Dimension
D
L
E1
E
e
A2
A
A1
b
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.810
1.100
0.032
0.043
A1
0.000
0.150
0.000
0.006
A2
0.750
0.950
0.030
0.037
b
0.220
0.380
0.009
0.015
D
2.900
3.100
0.114
0.122
e
0.650
0.026
E
4.800
5.000
0.189
0.197
E1
2.900
3.100
0.114
0.122
L
0.400
0.800
0.016
0.031
8-Lead MSOP Plastic Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
5F, No. 95, Minchiuan Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: [email protected]
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design,
specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed
by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
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